Boom



Filed April 1s, 1947 muuu/nw Patented Sept. 6, 1949 BOOM Andr Crot, North Hollywood, Calif., assignor to James B. Humphrey, Los Angeles, Calif.

Application April 18, 1947, Serial No. '742,432

11 Claims.

This invention relates to self-rigidiiying chain structures and more particularly to extensible booms of the articulated type. It has as its general object to provide an improved articulated boom that may be normally reeled upon a reel in a very compact condition, and which is adapted to be unreeled to an extended position in which it provides a rigid boom structure.

While it has been previously proposed to provide a boom structure comprising a plurality of articulated links adapted to be rigidified into a straight boom structure when projected from a reel, such devices in general depend upon the rigidifying effect ofthe abutting engagement oi the ends of the links, the hinges between the links being disposed at the upper extremities of the links in order to effect this result. With the links thus breaking downwardly, it becomes necessary to unreel the boom from .the lower extremity of the reel, and this requires that the diameteroi the reel be added to the height oi the structure above the level at which the boom is projected.

One of the objects of my invention is to provide a mechanism of this type in which the boom may be unreeled from the top of the reel instead of from the bottom. Thus, it becomes possible to reduce the overall height of the structure by the diameter of the reel casing.

Another object of the invention is to provide, in a chain of articulated links hinged at their lower extremities so as to break upwardly, mechanism for rigidifying the links as they are projected in a tangential line from the top of the reel, which mechanism is quite simple and yet completely effective and positive in operation. More specifically, the invention aims to provide a positive locking means for rigidifying the links, which locking means is positively actuated by the action of the links in moving into aligned relationship.

Another object is to provide locking mechanism comprising a series of individual elements that are duplicated in each of the link units, thereby reducing the cost of construction.

A further object is to provide an articulated boom mechanism having boom rigidifying locking means that is adapted to automatically release under the action of gravity as the boom is wound upon the reel.

A further object oi the invention is to provide an articulated reeling boom including automatically operative locking mechanism that is contained within the confines of the link structure of the boom, and requires no external actuating mechanism other than the drive mechanism for reeling and unreeling the boom. To this end, the invention contemplates an arrangement in which the locking and unlocking of the links is effected solely by the angular positioning of the links with respect to each other, together with the action of gravity on the locking elements.

Other objects of my invention will become apparent in the ensuing specifications, taken in connection withV the appended drawings, in which:

Fig. 1 is a side view of an extensible boom structure embodying my invention;

Fig. 2 is a sectional view through a portion of the boom structure;

Fig. 3 is a plan view of a portion of the boom structure; and

Fig. 4 is an inverted plan view of a portion of the boom structure. y

As an example of one form in which the invention may be embodied, I have shown in the drawings an extensible boom apparatus including a reel casing 6 mounted on a standard 'I and supporting a reel 8 upon which the improved articulated boom 9 of my invention is reeled.

The boom structure 9 is comprised of a plurality of rectangularlinks I0 which are hinged together at their lower corners by hinge pins I I. At the inner end of the boom, the innermost link I2 is attached to the reel B and at the outer end of the boom there may be provided a link I3 especially constructed for the lattachment thereto of any device vthat is to be carried by the outer end ofthe Iboom. For example, my improved extensible boom apparatus may be designed for use in a motion picture' studio and the link I3 adapted for the attachment of a microphone thereto, although it is to be understood that the invention contemplates the adaptation of the apparatus to many uses in which boom or crane devices of various kinds are required.

The reel 8 has a shaft I4 which is journaled in posts I5 at the upper end of the standard l. For extending and retracting the boom, the invention may utilize any conventional reeling means such as Afor example a crank handle attached to theshaft I4 and applying rotation directly to the reel" 8; Alternatively, the boom may be extended by applying a drive directly to the tangential portion of the boom extending horizontally from the top of the reel, as shown in the drawing. `For example, the inner Walls I5 of the links I0 may be provided with rack teeth I'I adapted to mesh with the teeth of a drive pinion I8 mounted on a shaft I9 journaled in the mouth 2II of the casing 6, and rotated by a crank handle 2 I;

Each link I0 includesthe web I6, a pair of side walls 22, and U- shaped end walls including shoulders 23 which may be roughly triangular in cross sectionj and flanges v2li which project from the upper edges of the transverse portions 23 to the upper edgesof theside walls 22. These end walls are disposed fat one end only of each link,

the opposite end having la shoulder 25.

'to4 the periphery of "in Fig. 1.2L,

The hinges include the hinge pins l I, which are extended through a central lug 26 on one end of each linkand apairof outerealjsrZl. on the o pposite engix ofeacyi lijnkwThe ears g'ldof one link embrace the lug 26 of an adjacent link.

The teeth I1 extend tranversely of the links,

occupying only about the central one-third "of the transverse dimension of a link. On either'Vv side of the line of teeth, thegbott v:Wall I6 ex.- tends unbrokenly to the plane, M

teeth l1 to provide bearing sur ce 8 lying in the same plane as said tips. Thebearigsurfaces 28 ride upon one or more rollers 29, 30A'Whkivh are journaled in the casing-6 and are dis'psed'bemeer; the firiveieioa and .theadiaeent Pelripher'yr of lthe 'releld I'Jfirtinl of the 'b'oc'i'ml when the' latter` is ullyf'reeled'. M'IVhat isp Vthe nearest a'oedsufnoionny farffrom the fuuy 1.1.1 ,the .lQckng j be 'described h after:

are adapted to'ride v.benealtl'i oneo 'more idler The .rneansfdrrigidif 1l' .l n in comprises Simply a'seriesof-i1'atonn gigolo/mon of indicated generally atf3r3.r Each 1k 33h`a onefe- ,bifurcated,to'pprovideapai vjf-arii's 31H which fare 'hinged 'u'DOnf a @H5351 hef ends .'Qf` which. are rnounted- .in fthe, lugs 21.Wh'ich :project upvvfarbll'yV from thelshouldersf'.; Each hook 33l1as ano'pposite' end Vpo n "31. which fissufiiciently narrow to vbe received Between thearn Y `34.0ffan adjacent hook,V .Each end portn .3.1 is prv. ded With an upwardly projectin `g.;javv `3.8 ivshich is adapted to snugly engage the'hin'ge pin 35 ofthe 'adjacent laftchhink.,.l

}The endsof theaY ect- Y ing fingers 3.9` which.A a l dapted rto be `engaged by the angesjzli of ,adjacent links 'to Vcontrol the movement of. the latchZLOKS'.

The operation'of theappar'atus of iiivenl-` H011 .will 110W P@ fieribeeflefgely.1m,@Qnnecin With Fig. 2', inv :which anurnber .ofstations along the patnof transition-sofialink,from'the reel to thejrigidied portonofotheQboom.and vice versa are indicated at ,a,. by .'c`d ,Y d e', respectivelypin order ,to ,facilitate Qt "e ref ence nto v'these several stations of movement 'grimms ljoriiofV trio boom, in Which the'liilsyale M34.. dl'yllf the ,lawn hooks 33 Will constantly t'ed'todop by gravity Pm 3.51.11? be the rigidiejd release thisf from the yailjacent `ends ,o tion so'as`t V1.1111; nd's kinto ,Wlxlc Y hook of @he iosteoienm to `permit that iagpoh to the unlatched positions which are occupied by the latch hooks at stations a, b, and c. In

`these .posi

35 clear the undersides of thepins 35 so as'to v'permit the upper extremities of thelinksl to sep-Y arate as they break away from each other. In

this unlatchedvpositionof the latch hooks, the iihfgeg; t Y:lelt'itlue plane of the end Ysurfaces of t e lugs e., they project into the space between'the separated ends of the adjacent links.

. At this. point it may'be noted that the link at portion 0f. the. ,.0 hook of such sup eravitythe.'

thehingebfetvY/ee tins-11 d, causingth'l n' 35S'llfC-e1llv link to thelilil'a ytion'of the Station ,Lcishghtly ,upper edges of" ,ofi4 the poom. ('s

tively free the" ja.

ence to ltlieili traoted, jood by oY Qs VrivesY at station 'bf its' ends Will have.

I j 'diyrromrooiioigftoiotioo o, motorrorespoiildingglatch jhook', prev usly ,inox/ed [to the unlatclifved position, will 11 hearrac'feldia' 75 position m which the' jawV s has moved undo@ the hinge pin which it formerly engaged. The latchhook of all ensuing links in the reeled portion of the boom will occupy a similar position.

In the reverse operation, i. e., the projecting operation, as the link at station b moves toward station c, the gap between the adjacent ends of these respective links will gradually be closed, and the anges 24 of the link at station b will engage the fingers 39 of the latch hook of the link at station c, moving the hook upwardly to its latched position. It may be noted that the link at station c has already been moved into a position of complete alignment with the rigidii'led portion of the boom, and slightly above that position, as the result of riding over the roller 30, and that consequently its latch 33 will be in a position where the jaw 38 may clear the adjacent hinge pin 35 as it moves to latching position.

When the link of station c has arrived at station d, its latch hook will have been moved to the fully latched position, and as this link'moves on to station e and subsequent positions of projecting movement, its latch will be rigidly secured in the latched position by the engagement of its lingers 39 against the anges 24 of the succeeding link.

In moving from station c to station d, a link will be permitted to drop back slightly from the raised position it assumed in station c, in order to assume a position in alignment with the rigidi ned, projected portion of the boom and in order to cause the jaw 38 of its latch to securely engage its coacting hinge pin 35. As the link travels through position e, it will be pulled downwardly by the weight of the projected portion oi the boom, tightening the engagement between jaw 38 and pin 35 and forming a substantially rigid structure with the projected portion of the boom. In this connection, it is to be noted that the substantially abutting relation between the ends of adjacent links cooperates in rigidifying the boom, resisting any substantial downward bowing oi the boom. Beyond the drive pinion I8, the boom is supported by the engagement of the rigidied portion thereof between the pinion I8 and the roller 3 I, the pinion I8 taking the down load and the roller 3| taking the up load resulting from the tendency of the boom to fulcrum about the pinion I8 under the weight of the projected portion. Thus the boom is supported by cantilever action in a horizontally projecting position.

With the boom thus supported and actuated from rigidied to broken condition and vice versa, it may be readily moved longitudinally by rotating the handle 2 I, thereby transmitting drive through the teeth of the pinion I8 to the rack teeth I1.

I claim:

1. In a self-rigidiiying chain structure, a plurality of links hinged to each other on axes adjacent one side thereof, and a corresponding series of locking elements each pivoted at one end to one end of a corresponding link and having its opposite end formed with means for locking engagement with the link adjacent the other end of said corresponding link, each of said locking elements being further provided with means arranged to be engaged by the link adjacent its pivoted end as the latter link and said corresponding link move into relative positions for 'rigid interconnections, whereby to positively move said locking element into saidlocking engagement.

2. In aself-rigidifying chain structure, a series of links hinged to each other on axes, adjacent Vone sidek thereof, and a corresponding'series of locking elements, each pivoted at one end to one end oi a corresponding link on an axis adjacent the other side of thechain structure-and having its other end formed for locking engage-y ment with the link adjacent the lother end of said corresponding link, whereby to rigidify the` two links with reference to each other, and each of said locking elements having means that is engageable by the link adjacent its pivoted end as the latter link and said corresponding link move into relative positions for rigid interconnection, whereby to positively move the locking element into said locking engagement.

3. In a seli-rigidifying chain structure, a series of links hinged together on axes disposed adjacent one side thereof and a corresponding series of locking elements each pivoted at one end to a corresponding link and having its opposite end projecting beyond the other end of said corresponding link and formed` for locking engagement with the link adjacent said other end, and each Vof said locking elements having means positioned to be engaged by the link adjacent its pivoted end as that link and said corresponding link move toward relative positions for rigid connection with each other, the last-mentioned link being adapted, through said engagement of said locking element, to positively move the latter into said locking engagement.

4,.l A self-rigidifying chain structure comprising a plurality of links pivoted together on axes disposed on one side oi the chain structure and a corresponding series of locking elements, each pivoted at one end to an end of a corresponding link on a pivot axis arranged adjacent the other side of the chain structure, and each having its opposite end projecting beyond the other end of said corresponding link and formed with means for locking engagement with the link adjacent said other end, whereby to establish a rigid relation betweenthe two links, and each of said locking elements having at its pivoted end a finger projecting toward the hinge at that end of said corresponding link and positioned to be engaged by the adjacent end of the link adjacent said pivoted end, as the latter link and said corre-v sponding link move into relative positions for rigid interconnection whereby to positively move said locking element into said locking engagement.

5. In a self-rigidifying chain structure, a Vplurality of links hinged together on axes disposedv adjacent one side of the chain, said links being rectangular in longitudinal section transverse to the hinge axes and having end surfaces adapted to establish substantially abutting relation in the relative positions of the links in which they are to be rigidly connected, and a corresponding series of locking elements each pivoted at one end to an end of a corresponding link on an axis disposedadjacent the other side of the chain structure, and each having its opposite end formed for locking engagement with the link adjacent the other end of said corresponding link, each of said locking elements having, at-its pivoted end, means positioned to be engaged by the link adjacent said pivoted end as the latter link and said correadjacent one side of the chain structure anda. corresponding series of locking elements eachpivoted at one end to a corresponding link on anv aX'is disposed adjacent the other side oi the chain Vadjaceiit the 'loivei side of the chain with said links, a. corresponding s'ei'fies 5i' le Y said locking 'eleiiientsv having aliy .means positioned to be engagedv by Vthe Yadjacent 7 f structure and having its 'opposite' ein famed latiniY iieafn's 'for locking engagement 'With the dafent 'ensei nie preeedingiinkgsaid ipe ng elem' is tending to as'suiiie `r"e`leasdI positions-iii 'W hing'ing movementfbettveentiie'liiiks 'nd'e'achof saidV locking eleinehts'ha pivoted end meansfp'ositionedfor engagei the'succeedi'ng link'asthe latter link -acorresponding link moveV toward the -ati sitionsin whichl they vare-telde' rigidlyc A' together, whereby to positivelllnfiil'e-the element to theV Ylocking position;

n a chain structure' 'embed-'ying a :pluralitir of links hingedv together fand j adapted te' besoins automatically rigidiied i in moving4 'nteV ali'gniieiit oiia'ihorizontalaiiis froi'n p'sitix'ns the links lare broken do'ivniialrdlyilith r" ce"v to Said iiorizontai axis, saidhinlge Vlo isposedy in said horizontal alignment, inl ceinli't' n ng elements each pivoted atone'e'nd to end'oija corresponding link and having its opposite end formed'for lockingconnec'stioii with theiadjaefnt endY of'V a preceding link 'vvheieioyv tomestalelish a rigid 'connection'betweentheI t" '1ink's,'each;o s; pix/sea end jacent link, and a pair or" side walls pi'ioie g j away from the plane ,of the hinfge'aki's, and a se:

ries of locking elements each includin'g'a Taifiie catedV portion and a hinge pin having ei'ids' mounted in the respectiveside l e'-`A spon'd-ing link and an intermediate "portion on which said bifurcated portionofthe lockinge'ler' ment is pivoted, Ieavczli lockingelei'n'e i its 'opposite end a centi'fallydisposd able between the furcations pf the iockm" succeeding link moves from a'tilt'ed' os ioiY o; aposition of alignment with sfaidc rije'po infgl linlgfwhereby to positivelyfno'ire said hoo` i' engagement with its respective hiig'e'fpin; i

Vv9. In a` self-rigidifying 'chai'r structure, alpinrality of links, U-'s'hap'ed in -e-ross set-ioi'i, ilfafclifinLV cli-'ifd'irig a Webrwall hinged "to the {"or'e's ndiiig Walls of adjacent links and parall'e` projecting away froml the plane'oi' e hinges,

anda corresponding series"'of lookin 1 leiients70 each having 'a lo'ifurca'tedQend"a'nd hii'igfe extending througnthe iurcajtion's K I n mountedV in the side- Walls a corresp 111g Vlink at one ena tneronfthe eprisitven qfgt'he' 'locking element having a centrally dispsed hook re-ceivabie between in@V iur'atins of* the; locking eleinie'nt y'ofthe preceding link vand engageable With the locking pin of 'the lat'teiff`li1i11 i-I 'tot establish la rigidconnection between Said crrspbndi'ngflink and said preceding link, each of 'thedin-ksjhaving at' its endl oppositeth'e end` to Whichthe locking element is pivoted, a-pair offanges projecting tm Ward each other and each of the' loeking'eieinents having' its fureations provided, attiiepivoted eii'c'is thereof, withV lingers projeetingtoiirard'L the adjaeentv hinge anden'gageablejwi'th thejendf'a'ces f said nanges @fine succeeding link as said-succeeding link moves from a tiltedpositioi"to'apoe sitio'noi alignment with said correspondingrlink, whereby to positively move the` locking/element into locking conneetionv With-,the preceding link, said locking elementfbeing 'movable iin'dei" the i'iiiluence of Agravity t'oja loweredpsition'disen- 'g'aged' from Yits Yinterloc'zkin"'gV liingefpin fiivl'i'en` vthe succeedingV link` is tilted downwardly With` refer: Y

encejto said oorres'pondinglink 10. 'In a'self-rig'idifying Vthain structure,v 'a series of links hingedto'getherfo'r ino'ie'i'nent from free-hinging positions broken upwardlytwithreference to eachother toapositionfof 'rigid association: for projection ina n'veiticailpath'in which the'liinge axes are Idisifio's`ed at the ylower sides ofv tineV links, (a Yplurality io'filocking elements each'pivoted at one er'idjto corresponding link above thehinges thereof.' andhaving' itsV oppositeY end Vformed for lockingV marinestion' Withthe Yacijac'ent end .of thelinkthatprecedes said'corresponding link" in the direction' of projection, whereby to establish a rigidconnectionbetween the two links, guide means for conning the rigidi'ed'portion of the Vstructure finthe path of projection and means for engaging t'lieunderside of a link intermediate the'freeehinging linksand the rigidied links for holding said, intermediate link in a raised position'inwhich its"lockingele ment may freely disengage itself :under the i'niiu en'ce'jo-f giavitywfroin its interlocking connection with said preceding link.V Y

11. A reelablearticulated boom 'structurezc'omprising 'a 'plurality jo'flinks' hingedtogether "on axes disposed adj'ac'entone 'side ofthe' b'oiofm structure, and a corresponding series'bfflockii'i'g elementseach pivote'd',,at 'one 'endt'o an Aend-of a corresponding link and having fits,l opposite "e'nd proj'ecting'beyond the other end of saidcorre-V spending link and formed fof'iockng ensagementv with'the precedingv link in 'order .toestablish a Yrigidifying connection/between Vthe two ylinks,

and each of'said locking' elements having at Aits pivoted end,VV means arranged to'be' engaged 'by a succeeding linkas the latterfflinik nim/ies from a. position inclined withfrijefereiieej tofs'aid "oorre-"- spondinglink to aipositionjof ial'ig'niiiehtfwith'said corresponding' link,l iwi'iferebly *to "positivelyV vr'iiovej th'elo'cking element into 'said locking `"eng'age'i'ii'ent' with the preceding link. i 1 Y ANDRic-Rofr.

Vlasifgsriaiiess.,climi file of 'this patent: l

UNITED sfiATnsfPAfrNTs,

Y Datei The following references vare of 'record Yinthe Number i Y"Name i 4 2,143,953 v kLeRoy V 1 2,251,303` ri V-Washington sus 5., 

